Cervical cancer, one of the most prevalent human tumors, is associated with papillomavirus (PV) infections. PV's induce neoplastic transformation of human keratinocytes in-vivo and in- vitro and are associated with premalignant lesions or dysplasias. Protection against PV infection is thought to be humorally-mediated and, at least in the bovine system, appears to be the result of a response to the PV L1 capsid protein. We intend to define the linear antigenic epitopes of several PV L1 proteins which are recognized during host infection. Three virus types will be studied: BPV-1, HPV-11 and HPV-16. The HPV were chosen because of their importance in cervical neoplasia and BPV- 1 and HPV-11 were chosen for the availability of both virus and assay systems to evaluate viral neutralization. The experimental approach is as follows: serum from infected or immunized calves and from infected women will be screened for reactivity with bacterially-expressed L1 proteins; L1-immunoreactive sera will be screened further by a hexameric oligopeptide method which allows the precise epitope localization; the surface location of epitopes will be determined by reaction of serum samples with intact virus; linear epitopes will then be assayed for their ability to mediate virus neutralization (by in vitro and in vivo assays) as well as their role evoking type-specific antibody responses. Immunocytochemistry of "typed" surgical specimens; and finally, type-specific epitopes will be used to generate monoclonal antibodies for diagnostic pathology and virology. These approaches will use several unique and valuable reagents: 1) Serum from 25 calves successfully vaccinated with a BPV-1 fusion protein which protected against subsequent challenge with virus, and 2) serum from 55 male patients with known, typed HPV infections. The outcome of these studies may have very significant therapeutic, diagnostic, and biological applications. Two animal models will be used to accomplish this project: 1) Hyperimmune calf sera from a successful BPV-1 recombinant DNA vaccine mode, and 2) the athymic mouse xenograft model.